TA Level Question

[ncpool]

What does it mean when it says the ideal TA level is 70-90+? Does that mean any value over 90 is ok? I don't see that on any of the other values.

 

[Bama Rambler]

That means that the ideal level is anywhere between 70 & 90 ppm but if it goes a little above 90 it might be ok too. Ideal for you is where ever it needs to be to keep your pH from raising to rapidly or swinging wildly. I've seen people run it at 60 and be fine and also seen it at 110 and be fine.

 

[bk406]

I'm not sure you should read too much into the term "ideal". Ideal pH is 7.4 or so, but 7.8 or 7.2 is ok.

TA is one of those things though that can be in a larger range, IMO. If you have a SWCG, a lower TA may be indicated to keep the pH from rising too fast. If on the other hand you use trichlor, which is acidic, a higher TA would be better to keep the pH from falling too fast.
As a general rule, a higher TA is indicated if your pool's pH tends to drop fairly often or fast, a lower TA if your pH tends to rise. Others can give you a more detailed explanation, but thats it in a simple nut shell with out all the rig-a-ma-ro chemistry that we can get bogged down in sometimes.


Edit: Bama typed faster than me

 

[ncpool]

Guys, thanks for the quick responses. There is a page on Pool School entitled recommended values. That's where i saw this.

You guys have helped me understand TA is really a buffer for PH. I had never made the connection before. Thanks a lot for your help.

 

[chem geek]

You guys have helped me understand TA is really a buffer for PH.

Not only a buffer for pH, but a source of rising pH in its own right. I think that's probably what you meant since having TA as a pH buffer is what most people think about. However, they incorrectly assume that a higher TA would therefore provide more pH stability, but being a source of rising pH itself, due to carbon dioxide outgassing, a higher TA can make the pH less stable (i.e. rise faster).